Rotation mechanism for rock drills



N A M F F U H C. M.

ROTATION MECHANISM FOR ROCK DRILLS Filed Aug. 17, 1939 \Q\\ III \H Q N DIi Q m. @am v Y N\ L -Y Q .NM NN m. ,g rf. E

INWNTOR. 19K/T75 A TTORNE'Y Patented July 16, 1940 PATENT OFFICERorA'rioN MEcHANrsM Fon ROCK DRILLs Mervin C. Human, Denver, Colo.,assignor to Gardner-Denver Company, Quincy, Ill., a cor'- poration ofDelaware Application August 17,

6 Claims.

My invention relates to improvements in rock drills and is moreparticularly directed to means for rotating the drill steel.

The principal object of the invention is to provide a rotation means forthe drill steel which is operated upon the reciprocation of the pistonhammer in one direction of its travel.

Another object of the invention is to provide a rotation mechanismwhereby rotation of the steel ceases when the force necessary to rotatethe steel exceeds a certain limit.

Still another object of the invention is to provide a rotation mechanismwhich will become inactive if the resistance to the rotation of thepiston becomes abnormal.

Further objects of the invention will herein* after appear, and to allof these ends the invention consists of the features of construction,arrangement of parts, and combination of elements, substantially ashereinafter fully described and claimed in the specification and shownin the accompanying drawing, in which:

Figure 1 is a longitudinal sectional view showing what is known as adrifter drill with the improved rotation mechanism associated therewith.Y

Figure 211s an enlarged sectional view of the ring and ratchet head onthe line 2-2 of Figure 1, and

Figure 3 is an enlarged in detail the ratchet ring. 1

Briefly the invention about to be described relates to a rotationmechanism for rock drills and is more particularly adapted to such ameans used in connection with a drifting drill.

Ordinarily when operating a drifting drill, the operation of the drillis determined by the amount of penetration of the steel. In other words,there is a possibility during the penetration of the steel for the steelto stick, causing the hammering action of the drill to stop. This resultis objectionable in that it requires the 4closing of the operating fluidvalve, the movement of the drill backwardly and a resumption of thedrilling operation. With the present improvement the reciprocatinghammer serving to impart blows to the drill steel continues in its'operation even though rotation is not imparted to the drill steel. Withsuch a mechanism it has been found that continued operation of thepiston hammer serves in some instances to free the steel, permitting itsultimate rotation through the mechanism of the hammer. Broadly theinvention relates to what is known as a slip rotation means for rockdrills and is of such a sectional view showing character that when theload on the steel exceeds a certain limit, rotation of the steel isinactive.

Referring to the drawing in detail the numeral I indicates a drillingmotor of the drifter type, having suitable means for mounting it upon aconventional guide shell indicated at 2. 'I'he motor I is composed ofacylinder 3 within which is a reciprocating hammer 4. As is customary ina structure of this type, the piston 4 strikes the end of a drill steel5 during its reciprocation, the steel being supported in a chuck endcarried by a drilling motor.

The rear end of the cylinder 3 is provided with a valve chest Ii havingtherein a sleeve valve 1 supported by a valve plug 8 through whichpasses the conventional rifle bar 9 having at its rear end a ratchethead IIl provided with spring pressed pawls II which are engageable witha ratchet ring I2. The rear end of the cylinder 3 is closed by abackhead I3 provided with suitable connections for both water and airand a throttle valve for controlling the flow of air t0 the sleevevalve 1. The backhead, cylinder and chuck end are maintained inalignment by suitable side rods, not shown, which carry the usualcushioning springs, permitting a slight movement of the parts mentionedabove with relation to each other. l

l As disclosed in Figure 1, the ratchetring Vis composed of twosections, the adjacent faces of which are provided with a number ofsockets I 4 which receive therein the ends of expansion springs I5. Thepurpose of the springs being to hold the sections of the ring apart.

With the structure shown in Figure l, it will be observed that thechamber for the ratchet ring is formed by the outer face of the valveplug and the inner face of the backhead and the sections of the ring areforced outwardly against these faces when the ring occupies the spaceshown.

The inner surface of each section of the ring is provided with ratchetteeth I6 as shown in Figure 2 and engageable with these teeth are thepawls II carried by the ratchet head I0. I

During the operation of the drill, it will be obvious that when fluid isadmitted to the sleeve valve 1, movement of the valve controlsreciprocation of the hammer 4 and with the type of rotation disclosed asthe hammer moves downwardly over the rifle bar 9 and by reason of thespring pressed pawls engaging the sections of the ring I2, the rie baris free to rotate, permitting a direct outward movement of the hammer tocontact the steel. When the valve 'l is shifted to cause the return ofthe piston 4, the pawls Il engage the ratchet ring, holding the riflebar 9 stationary, rotating the piston 4 during its backward movementthus imparting rotation to the drill steel through the conventionalchuck engageable by both the hammer and steel.

It frequently happens in operation of a drill of this type, that thestrain imparted to the steel is greater than that of the rotationmechanism, the result being that the drill stops in operation. Toprevent this and at the same time permit the continued engagement ofthereciprocating hammer Withthe steel, the ratchet ring is formed of twosections held apart by springs, permitting slippage of the ratchet ringwithin its chamber, thus rendering inactive the rotation of the pistonhammer and ultimately the steel.

With the invention just described, it is obvious that Ithe ratchet ringis frictionally held in place and this friction may be regulated by thetension of the expansion springs l5 together with tension exerted uponthe side rods.

From the foregoing, it is thought that the construction, operation andmany advantages of the herein described invention will be apparent tothose skilled in the art without further description, and it will beunderstood -that various changes in the size, shape, proportion andminor details of construction may be resorted to without departing fromthe spirit or sacri'cing any of the advantages of the invention.

What I claim is:

1. In a uid operated tool, the combination of a cylinder member and aclosure at its rear end forming a chamber therebetween, of areciprocatory piston in the chamber, a riie bar engageable with thepiston and having a head in the chamber, a ratchet ring in 'the chambersnrrounding the rifle bar head and having a ratcheting connectiontherewith, and resilient means carried by the ring for frictionallyholding the same against movement during normal operation of the drill.

2. In a iiuid operated tool, the combination of a cylinder member and aclosure at its rear end forming a chamber therebetween, of areciprocatory piston in Ithe chamber, a rifle bar engageable with thepiston and having a head'in the chamber, a ratchet ring in the chambersurrounding the rifle bar head and having a ratcheting connectiontherewith permitting rotation of the hammer during one of its movements,said ratchet ring carrying resilient means for holding it againstmovement during normal operation of the drill, and said resilient meanspermitting rotation of the ratchet ring during abnormal operations ofthe drill.

3. In a fluid operated tool, the combination of a cylinder member and asteel retaining chuck connected theretopa closure for the rear end ofthe cylinder forming a chamber between the two, a reciprocatory pistonin the chamber, ratchet means actuated by the pistonfor impartingrotation to the chuck, said ratchet means including a ring frictionallyheld during the normal operation of the drill, said ring being formed oftwo like parts separated by resilient means, and said resilient meanspermitting the movement of the ring. as a whole during the abnormaloperation ofv the drill.

4. In a fluid operated tool, the combination of a cylinder and a steelretaining chuck carried thereby, a backhead closing the rear end of thecylinder and forming the chamber therebetween, a reciprocatory piston inthe cylinder serving to impart rotation -to the chuck, a ratchet meansin the chamber `engageable with the piston for rctating the same duringcertain of its movements, said rotating means including a two .part ringpositioned within the chamber, and means serving to separate the twoparts of vthe ring holding the same against movement during normaloperation of the drill and permitting movement of the ring duringabnormal periods of operation.

5. A rock drill 'comprising a cylinderr having a piston chamber, apiston reciprocable in said chamber, rotation mechanism for rotating thepiston including a riiie bar having a head, a ratchet ring surroundingthe rifle bar head and rotatable within a chamber formed within thedrill, said ratchet ring being composed of two parts, and meanspositioned between the parts normal operation of the `drill andpermitting their movement toward each other during abnormal operation ofthe drill.

MERVIN C. HUFFMAN.

